Magnesium sulfate
[CAS# 7487-88-9]

Identification

• Classification: Inorganic chemical industry >> Inorganic salt >> Metal sulfides and sulfates
• Name: Magnesium sulfate
• Synonyms: Magnesium sulfate - dried
• Molecular Formula: MgSO₄
• Molecular Weight: 120.36
• CAS Registry Number: 7487-88-9 (139939-75-6)
• EC Number: 231-298-2
• SMILES: [O-]S(=O)(=O)[O-].[Mg+2]

Properties

• Solubility: 33.7% (water, 20 °C)
• Density: 2.66
• Melting point: 1124 °C

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H302-H312-H332
• Safety Statements: P261-P264-P270-P271-P280-P301+P317-P302+P352-P304+P340-P317-P321-P330-P362+P364-P501

Discovery and Applications

Magnesium sulfate was discovered in the mineral springs of Epsom, England, in the 17th century, hence its name Epsom Salt, which is now commonly used to refer to magnesium sulfate heptahydrate. The compound, which is composed of magnesium, sulfur, and oxygen, can be found naturally in mineral deposits or synthesized by combining magnesium oxide or magnesium hydroxide with sulfuric acid.

Magnesium sulfate is often used as a laxative to relieve occasional constipation. It draws water into the intestines, facilitating bowel movements. It also acts as an antacid, relieving heartburn and indigestion by neutralizing stomach acid. Epsom salt baths are popular for their muscle-relaxing and pain-relieving properties. When dissolved in warm water, magnesium sulfate can be absorbed through the skin, helping muscles relax, reducing inflammation, and relieving stress. This makes it a common remedy for muscle aches, sprains, and other minor injuries. In medical settings, magnesium sulfate is used intravenously to treat conditions such as eclampsia and preeclampsia in pregnant women and to prevent seizures. It is also used to treat severe asthma attacks, hypomagnesemia (low magnesium levels), and as a tocolytic to delay premature labor. Magnesium sulfate is a key ingredient in emergency medicine, especially in the treatment of certain types of heart rhythm disorders. Its ability to stabilize heart rhythm makes it essential for treating life-threatening conditions such as Torsades de Pointes.

Magnesium sulfate is widely used as a fertilizer to provide essential nutrients to plants. Magnesium is an important component of chlorophyll and is required for photosynthesis, while sulfur is key to protein synthesis. Magnesium sulfate helps correct magnesium deficiencies in the soil, thereby promoting plant growth and increasing crop yields. As a soil conditioner, magnesium sulfate helps improve soil structure and nutrient availability. It is particularly beneficial in sandy or acidic soils that are deficient in magnesium and sulfur, contributing to healthier plants and higher yields.

Magnesium sulfate is used in the production of a variety of chemicals, including in the paper and textile industries. Its reactivity makes it a valuable agent in the preparation of certain dyes, detergents, and fireproofing materials. In water treatment, magnesium sulfate helps control water hardness by precipitating calcium and magnesium ions, thereby reducing scaling in pipes and boilers. This improves the efficiency of hot water systems and extends their service life. In the construction industry, magnesium sulfate is used as an additive in cement and concrete. It improves the physical properties of these materials, increasing their strength and durability.

References

2024. Antiepileptic-drugs/Magnesium-sulfate. Reactions Weekly, 1994(1).
DOI: 10.1007/s40278-024-55074-4

1990. Adjusting the loading dose of magnesium sulfate for tocolysis. American Journal of Obstetrics and Gynecology, 163(3).
DOI: 10.1016/0002-9378(90)91090-y

1979. Cardiac effects of magnesium with special reference to anaesthesia: a review. Canadian Anaesthetists’ Society Journal, 26(3).
DOI: 10.1007/bf03006978"